Frame-type dump scrapers

ABSTRACT

A dump scraper includes a frame having spaced-apart base portions adapted to be movably mounted on opposite sides of a dump. The frame includes legs extending upwardly toward one another from the base portions. A one-piece boom is pivoted to one of the base portions for pivotal movement in a vertical plane parallel to the legs. The boom receives support from the legs against substantial lateral deflection.

United States Patent Inventor Fritz Schade Dortmund, Germany Appl. No.796,130 Filed Feb. 3, 1969 Patented Jan. 26, 1971 Assignee Gustav SchadeMaschinenfabrik Dortmund, Germany Priority Feb. 12, 1968 Germany1,556,682

FRAME-TYPE DUMP SCRAPERS [5 6] References Cited FOREIGN PATENTS 691,3144/1940 Germany 648,720 11/1962 GreatBritain ABSTRACT: A dump scraperincludes a frame having spacedapart base portions adapted to be movablymounted on op- 7 Claims 5 Drawing Figs posite sides of a dump. The frameincludes legs extending up- US. Cl 198/36, wardly toward one anotherfrom the base portions. A one- 214/10 piece boom is pivoted to one ofthe base portions for pivotal Int. Cl Bg 65/28 movement in a verticalplane parallel to the legs. The boom Field of Search 214/ 10; receivessupport from the legs against substantial lateral 198/36; 37/190, 191deflection.

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ATTORNEYS FRAME-TYPE DUMP SCRAPERS The present invention relates to adump scraper with a frame spanning the dump, which frame can betraversed along the dump on rails laid at either side thereof in theneighbor hood of the dump.

Dump scrapers are known which run on two rails located at one side ofthe dump. In these systems, the weight of the scraper boom has to becompensated for by a counterweight arranged at the side remote from thedump. The amount of space occupied by this kind of scraper system atthat side of the dump from which it operates, is therefore relativelylarge and this is a drawback which is particularly severe in cases wherethe available ground area is very restricted. Since, with this kind ofsystem, the scraper boom is fixed or held only at one end, the maximumboom length, which is what detennines the width of the dump, is limitedbecause of loading factors.

Also known are frame-type scrapers with folding booms. A folding boom ofthis kind consists .of two sections with separate drive arrangements,chain sprockets and the like. It requires guide means at the boom tipand also an additional joint at the knee point. This makes the device arelatively complex one from the constructional point of view and it istherefore also expensive. Also, where the dump material has compacted atall, frequently transmission difficulties arise at the knee point in theboom. Finally, in this kind of system too, the maximum dump width whichcan be handled by the folding boom is limited by the same kind offactors which restrict the device just mentioned.

Again, dump scrapers of frame design are known which employ separatescraper booms operating at either side of the dump. Here, both the boomshave'separate drives, separate pivot bearings and separate lifting gear.As a consequence of the doubling up of all the boom functions, theequipment becomes more complex and less reliable in operation.

It is the aim of the invention to overcome these drawbacks and to createa frame-type dump-clearing device which occupies less ground area, alsorequires less outlay in terms of joints, lifting gear, boom guides andscraper chain drives, thus being cheaper and more reliable in operationthan known equipments, and which, finally, can also span very widedumps.

In accordance with the invention, there is attached to the frame at apoint thereon near the ground, at least one onepiece scraper boom ableto pivot in a vertical plane, said boom having a length approximatelyequal to the width of the dump across its base and preferably extending,when in the raised position, out beyond the frame with its tip portion.

In accordance with a further essential feature of the invention, thearrangement is so contrived that the pivoting scraper boom is laterallysupported against the leg of the frame opposite to the one to which itspivot bearing is fixed. With this kind of design of the frame-typescraper in accordance with the invention, the scraper boom isaccordingly supported not only on the pivot bearing arranged near thebase of the dump, but also, at a large interval from this bearing, uponthat side of the frame which is opposite to the side at which the saidbearing is located, the support in the latter case being lateral supportagainst the horizontal forces acting upon the boom during operation ofthe system. Due to this lateral supporting of the scraper boom the boomlength can be considerably increased without the horizontal forcesacting upon the boom in the bending mode, becoming undesirably largewith consequent bending deflection of the boom. The lateral supportingof the boom moreover provides the substantial advantage that thetransverse forces stemming from the horizontal sheer forces are largelyisolated from the pivot bearing of the boom. It is therefore possible toclear even very wide dumps using a single boom spanning the full widthof the dump base.

In a preferred embodiment of the invention, the frame is provided with afork or slot in that leg which is opposite the one carrying the boompivot or bearing, in which fork or slot the forward portion of thescraper boom is located and can thus be supported against lateralforces. The boom is thus in this case guided in the frame slot at thatof its ends opposite to the one through which it pivots, and dependingupon the direction of traverse of the frame or the direction of actionof the horizontal shear forces, is supported against one or other of thesides of the slot.

In accordance with a further essential feature of the invention, thedump scraper is equipped with two parallel-disposed scraper boomspivotable in a vertical plane, which supported laterally at either sideof that leg of the frame which is opposite the leg carrying the boompivots. The two booms are in this case located at the same side of theframe in the neighborhood of the base of the dump, preferably pivotingabout a common pivot pin or coaxial pivot pins and at such an intervalfrom one another that one boom can bear against the frame from one sideand the other boom likewise from the other side. This kind of design ofthe dump scraper is distinguished in particular by high performance andsimplicity of construction. The two parallel-arranged booms willpreferably be linked with one another at their tips through a spacer orthe like which permits a limited degree of relative vertical movementbetween the booms so that in operation they can be vertically staggeredin relation to one another in each case by the amount of the depth ofrake.

It is advisable to provide on the cooperating faces of frame and boom orbooms, abutment and guide elements of wear-resistant material,preferably strips or the like, and in the case of the slotted frame legboth faces of the slot will have to be provided with elements of thiskind.

Advantageously, in accordance with the invention, the lateral supportingof the boom or booms will be such that between the lateral abutmentfaces of boom and frame leg, there is a clearance which is less than therange of elastic deflection of the boom at that point. In this case, thelateral support will in all cases exclusively be provided in conditionsin which the horizontal shear forces are still within the range ofelastic deflection of the boom. It is thus possible to raise and lowerthe boom or booms without the said abutment and guide faces being insliding contact with one another.

The invention will now be described with reference to the accompanyingdrawings, which illustratethe invention but in no restrictive sense.

FIG. 1 illustrates an elevational view of a frame-type dump scraper inaccordance with the invention;

FIG. 2 illustrates a plan view of the dump scraper of FIG. 1;

FIG. 3 is an elevational view of a further embodiment of the dumpscraper in accordance with the invention;

FIG. 4 illustrates the dump scraper of FIG. 3 in plan;

FIG. 5 is an end elevation of the connection between the two booms, attheir tips, considering the dump scraper of FIGS. 3 and 4.

The dump scraper of FIGS. I and 2 has a frame I symmetrical about itsown central plane, which spans the full width of the dump 2. The framecan be traversed along the length of the dump on wheels 3 which run uponrails 4 laid at both sides of the dump 2 beneath the level of the base 5thereof. At one side of the dump, a trench 6 is provided runningparallel with the rails 4 disposed there, and this trench contains aconveyor 7 and furthermore extends over the full length of the dump.Above the conveyor 7, a bracket 8 or the like is fitted to the frame, inwhich bracket a boom 10 is mounted to pivot about a horizontallydisposed pin 9. The boom 10 is thus pivotable in the vertical plane andfor the pivoting movement appropriate lifting gear is provided,consisting for example of a winch 11 the cable 12 of which is takenthrough a sheave of pulleys 13 to an attachment bracket 14,articulatingly connected to the boom. The attachment bracket 14 isconnected to the boom at a point between the center thereof and the tip15.

The scraper boom consists in the conventional way of the actual beam 10aon which the endless chains are so guided in the direction of the arrowP (said chains being connected together through scraper rakes 10b) thatwhen the boom is lowered onto the slope 16 of the dump, the rakes engagethe bulk material of the dump and scrape it in the direction towards thepivot bearing 9 and there it is fed over a platform 18 and a feed hopper17 onto the conveyor belt 7. During the clearing operation, theframe-type scraper is traversed along the dump on the rails 4. Aftereach pass, the scraper boom is lowered, using the lifting gear, by anamount corresponding to the depth of penetration of the rakes.

The frame 2 consists of the two legs la and lb inclined substantiallyparallel to the slope of the dump. The boom has a length such that atthe leg lib it extends beyond the frame, and, in the fully loweredcondition, shown in HQ. l in broken line, spans the full width of thedump. it is therefore possible, by means of the boom it) which is aone-piece design (i.e. has no intermediate joint) to clear the dump overits full width.

As FIG. 2 shows particularly well, the frame is provided in the leg llbas well as in the crosspiece lie, with a slot 19, the width of which issomewhat greater than the width of the boom across its external edges.The boom passes through the slot 19 and can be moved through it, theslot extending substantially over the full length of the leg. On the twosidewalls of the slot, narrow guide and abutment strips 20 and 21 areattached which extend substantially over the full length of the slot.The scraper boom 10 is provided likewise on both of its side faces whichface the said strips, with narrow guide and abutment strips 22 and 23which extend along the forward part of the boom, where it is guided inthe slot in the leg lb of the frame. The guide and abutment stripsconsist of a wear-resistant material and are so disposed that whateverthe angle of the boom, the boom strips can be laterally supportedagainst the slot strips at one or other of the sides of the slot.

Between the mutually cooperating strips 20 and 23, and 21 and 22, ineach case a small clearance 24 is available and this is within the rangeof elastic deflection of the boom. Under the effect of the horizontalshear force acting in the direction of the arrows Si or S2 and arisingduring the traversing movement of the frame along the dump, or as aconsequence of possible wind loading, the boom is therefore able to bearon the one hand against the guide strip 2t) or on the other against thatof strip 21, so that dangerously high deflections of the boom areprevented, even over long boom length, and the pivot bearing isprotected against horizontal shear forces. if no horizontal shear forcesare at work, then the boom is located centrally in a position in whichits two strips 22 and 23 are out of contact with the correspondingstrips 20 and 2i. in this condition, the boom can be swung by thelifting gear without the strips having any sliding contact with oneanother.

in the embodiment of FlGS. 3 to 5, the frame ll does not possess aslotted frame leg lib. The frame-type scraper is here equipped with twoscraper booms 3t and 33 which are connected to the bracket 8 in such away as to pivot about a common pin 9 or about two in-line pins. Eachboom is provided with its own independent lifting gear ill to 14, thiscorresponding with the lifting gear shown in FIGS. 1 and 2. The twobooms, which correspond with the boom it] of H68. 1 and 2 in design andlength, are arranged one beside the other at an interval from oneanother slightly greater than the width of the frame legs la and 1b. Thebooms are moreover connected with one another at their tips through astay or spacer 32 which fixes the interva! between the booms but permitsa certain amount of relative vertical or pivoting movement on theirpart.

As FKG. 5 indicates, this device consists for exampie of a spacer 32attached laterally to the boom 39, said spacer containing an elongatedhole 33 in which a roller 34 engages, said roller in turn being mountedon a bracket 35 carried by the boom 31. The roller 34 is guidedsubstantially without any play between rolling faces 36 defining theelongated hole. The elongated hole is of such length that the roller canmove upwards and downwards from the central position indicated, in

each case by an amount corresponding to the depth of rake of the booms.The two booms 30 and 31 are thus able to move in relation to one anotherin the vertical direction by an amount equivalent to approximately twicethe depth of rake of the booms or the raltes 10b, so that duringtraversing of the frame along the dump in one or other of the two possile directions,

the boom which is the rearward one considering the direction of travel,can be lowered further by the amount of the depth of rake, than the boomwhich is in the leading position.

in this case, the booms 30 and 35 are provided with a guide and abutmentstrip 37 and 38 exclusively at the particular side facing the leg inAccordingly, abutment and guide strips 39 and ll) are attached to theside faces of the frame leg against which the two booms with theircorresponding strips bear throughout their range of swing whenever theyrequire support. Between the strips 3'7 and 39, and 38 and 40, hereagain a clearance can in each case be provided which is within the rangeof elastic deflection of the boom at this point, so that physicalcontact between boom and frame leg only takes place in conditions underwhich the permissible deflection of the boom would otherwise beexceeded. Since the two booms have a fixed mutual interval, at all timesonly one of the two booms, generally the one which is leading in thedirection of traverse, can bear against the side of the frame leg. Theother boom will then be prevented from undergoing excessive deflectionby the cooperation of the spacer arrangement 32 with the laterallysupported boom,

In order to substantially isolate the pivot bearing 9 from the action ofany transverse forces, it is advisable to arrange for the clearancebetween guide and abutment strips on the boom or booms and the frameleg, to be small. The clearance may in fact be made virtually zero. Itis even possible to arrange for the boom or booms to be supportedpositively against the frame leg, through the medium of rollers.

Having thus described my invention, l claim:

1. A dump scraper having first and second spaced-apart base portionsadapted to be movably supported at opposite sides of a dump, said frameincluding first and second leg means extending upwardly toward oneanother from said first and second base portions respectively, one-piecescraper boom means pivotally connected to said first base portion forpivotal movement in a substantially vertical plane parallel to said legmeans, said boom having a length not substantially less than the spacingbetween said first and second base portions, said boom including a tipportion and having a length such that said tip portion projects beyondsaid second leg in raised positions of said boom.

2. The device of cla'm 1 wherein said scraper boom means is supportedagainst substantial lateral deflection by said second leg means.

3. The device of claim 2 wherein said scraper boom means has a lateralelastic deflection limit defined by a predetermined lateral distance,said scraper boom means being laterally spaced from said second legmeans a distance less than said predetermined distance.

4. The device of claim 2; and further including abutment and guide meanson said scraper boom means and said second leg means.

5. The device of claim 2 wherein said second leg means includeselongated slot means and said scraper boom means extends through saidslot means.

6. The device of claim 2 wherein said scraper boom means includes twoparallel spaced-apart scraper booms positioned on opposite sides of saidsecond leg means.

7. The device of claim 6 wherein said two scraper booms have tipportions and said tip portions are connected by spacer means, saidspacer means including lost motion means for providing limited verticalmovement between said two booms.

1. A dump scraper having first and second spaced-apart base portionsadapted to be movably supported at opposite sides of a dump, said frameincluding first and second leg means extending upwardly toward oneanother from said first and second base portions respectively, one-piecescraper boom means pivotally connected to said first base portion forpivotal movement in a substantially vertical plane parallel to said legmeans, Said boom having a length not substantially less than the spacingbetween said first and second base portions, said boom including a tipportion and having a length such that said tip portion projects beyondsaid second leg in raised positions of said boom.
 2. The device of claim1 wherein said scraper boom means is supported against substantiallateral deflection by said second leg means.
 3. The device of claim 2wherein said scraper boom means has a lateral elastic deflection limitdefined by a predetermined lateral distance, said scraper boom meansbeing laterally spaced from said second leg means a distance less thansaid predetermined distance.
 4. The device of claim 2 and furtherincluding abutment and guide means on said scraper boom means and saidsecond leg means.
 5. The device of claim 2 wherein said second leg meansincludes elongated slot means and said scraper boom means extendsthrough said slot means.
 6. The device of claim 2 wherein said scraperboom means includes two parallel spaced-apart scraper booms positionedon opposite sides of said second leg means.
 7. The device of claim 6wherein said two scraper booms have tip portions and said tip portionsare connected by spacer means, said spacer means including lost motionmeans for providing limited vertical movement between said two booms.